I've been working with the MegaCD lately, and after some research, I've come to understand how the ASIC works...for the most part.

The only thing I have been rather confused on is how the trace table is formatted and how it works. Looking at a manual didn't really help me much, and experimenting didn't help much. I've tried all I could to look it up, but to no avail. All I understand is that it involves a starting X and Y value, and X delta and Y delta values for each entry.

From what i remember you have a vector table giving :
- the X,Y start position in source image
- a list of X,Y vector which give you the X, Y step to add after each pixel read in source image.
you have as many entry in the vector list than the Y size of the output buffer (one vector per Y line).

can someone post a source code example on how to use this rotation feature of the mega cd ?
the official sega sdk documentation is not very crystal clear on how to use it, and I didn't find any open source example of this :/